microbiology an introduction test bank

Correct Answer: A

Rationale: The correct answer is A: chronic. A persistent infection that is not lytic but productive is characterized by ongoing viral replication without cell lysis. This type of infection is referred to as chronic, as it persists over an extended period. Latent infections involve periods of dormancy with intermittent reactivation. Slow infections typically have a prolonged incubation period before causing symptoms. Transforming infections lead to permanent alterations in host cell behavior. The key distinction for this question is the continuous viral replication without cell destruction, which aligns with the definition of a chronic infection.

Correct Answer: C

Rationale: The correct answer is C: urethra. Resident microflora refers to the normal, beneficial bacteria that inhabit a specific area of the body without causing harm. The urethra is one of the locations where resident microflora are commonly found. These bacteria play a vital role in maintaining a healthy balance and preventing harmful pathogens from colonizing the urethra. Blood (A), lung (B), and cerebro-spinal fluid (D) are not typical locations for resident microflora as these areas are usually sterile or have very limited microbial presence to prevent infections.

Correct Answer: D

Rationale: Certainly! The correct answer is D because all three options (A, B, and C) can be analyzed in the diagnosis of sexually transmitted infections. Genital ulcer secretions can reveal the presence of pathogens causing STIs, lymph node punctate can indicate systemic infection, and serum can be tested for specific STI antibodies. Therefore, all these clinical specimens are essential for a comprehensive diagnosis of sexually transmitted infections. The other choices (A, B, C) are incorrect as they individually represent important specimens used in the diagnosis process.

Correct Answer: A

Rationale: The correct answer is A: Obligate anaerobes. These bacteria can only survive in the absence of oxygen as they lack the enzymes needed for aerobic respiration. They typically use fermentation or anaerobic respiration for energy production. Incorrect choices: B: Facultative anaerobes can switch between aerobic and anaerobic metabolism based on oxygen availability. C: Obligate aerobes require oxygen for survival and cannot survive in anoxic conditions. D: Microaerophiles require low levels of oxygen for growth and are not capable of surviving in completely anoxic conditions.

Correct Answer: A

Rationale: Step 1: Gram-negative rod with safety pin appearance indicates bipolar staining. Step 2: Yersinia pestis is a Gram-negative rod causing bubonic plague. Step 3: Y. pestis has bipolar staining due to its unique F1 capsule. Step 4: The swollen lymph node and bacteremia are consistent with bubonic plague. Step 5: Therefore, the correct answer is A: Yersinia pestis. Summary: - B: Clostridium tetani causes tetanus, not characterized by a safety pin appearance. - C: Brucella melitensis causes brucellosis, not characterized by a safety pin appearance. - D: Pasteurella multocida causes animal bites infections, not characterized by a safety pin appearance.